Wrappers for tobacco articles are often cut out in the manner that an operator stretches a whole or a half tobacco leaf across a cutting table with a slightly protruding knife, following which the cutting is performed by a roller associated with the knife. When placing the tobacco leaf on the table the operator can attempt, firstly, that only undamaged or almost undamaged parts will lie within the cutting knife and so form part of the cut wrapper and, secondly, that it is made possible, according to the size of the leaf, to cut out at least one further wrapper from the same half of the tobacco leaf (right or left side). This provides for obtaining an optimum output, i.e. the greatest possible number of usable wrappers from a certain number of tobacco leaves, but it is a condition that the operator is sufficiently experienced and pays considerable attention while working, thus involving a relatively high wage cost per wrapper.
A still better output would be obtained if it were possible to cut out wrappers of different sizes, or different formats,from the same half of a tobacco leaf, but by the explained prior art method this possibility must be considered as excluded due to the cost problem.
The endeavours with a view to mechanizing the production of cigars and similar tobacco articles have also tended to increase the output and to reduce the expenses in connection with the cutting of wrappers, and a proposal in this respect is to perform the cutting in two steps, the tobacco leaves being at first cut into strips at appropriate width and parallel to the mid rib of the tobacco leaves, upon which said strips are trimmed at their ends and glued together longitudinally, somewhat overlapping each other, to form a continuous band that is rolled into a bobbin. Out of the tobacco band thus formed the desired size or sizes may be cut later on, appropriately immediately before they shall be used in a wrapper applying machine.
Prior to the strip cutting operation the tobacco leaves pass a photoelectric scanner controlling the trimming of the ends of the strips so as to minimize the waste caused by the trimming, and the scanner can further control the cutting-away of defective parts in the strips so that the wrappers cut out of the composite tobacco band can be expected to be faultless and without defects.
According to this technique the waste of tobacco as well as the need of manual work can be considerably reduced, but this requires a complicated apparatus for carryihg out the method and, moreover, each of the wrappers cut out of the tobacco band will frequently contain parts of two or more strips and will thus appear in varying colours, which is generally considered to be disadvantageous to the look of the finished tobacco article. This has occasioned a further development of the principle by which individual trimmed strip pieces of a sufficient length to produce the desired format are collected in separate bobbins by being transferred to a band-like web on which they are closely spaced in the longitudinal direction of the band and subsequently gripped between the windings of the bobbin formed by the web. The said strip pieces may consequently be used for tobacco articles that shall be free from colour variations in the wrapper, whereas only the shorter pieces are glued together into tobacco bands as explained above, but in return this modification of the method requires a further complication of the apparatus which will thus be extremely expensive to produce and also vulnerable to malfunction.